Pyridyl amines have been used to prepare Group 4 complexes which are useful transition metal components in the polymerization of alkenes, see for example, US 2002/0142912, U.S. Pat. No. 6,900,321, and U.S. Pat. No. 6,103,657, where the ligands have been used in complexes in which the ligands are coordinated in a bidentate or tridentate fashion to the transition metal atom, wherein the pyridylamide ligand is chelated to the transition metal with the formation of five membered rings.
Davies and Solan describe in WO 2005/095469 catalyst compounds that use tridentate ligands through two nitrogen atoms (one amido and one pyridyl) and one oxygen atom, wherein the tridentate ligand is chelated to the transition metal with the formation of five and six membered rings.
US 2004/0220050 A1 and WO 2007/067965 disclose complexes in which the ligand is coordinated in a tridentate fashion through two nitrogen (one amido and one pyridyl) and one carbon (aryl anion) donors, wherein the pyridylamide ligand is chelated to the transition metal with the formation of five membered rings.
The above mentioned pyridyl amide complexes are known to undergo insertion of an alkene into the metal-aryl bond of the catalyst precursor during activation (Froese, R. D. J. et al., J. Am. Chem. Soc. 2007, 129, 7831-7840) to form an active catalyst that has a tridentate ligand chelated to the transition metal with five and seven membered rings.
Kuhlman and Whiteker disclose in US 2010/0227990 pyridylamide complexes in which the ligand is chelated in a tridentate fashion through two nitrogen (one amido and one pyridyl) and one carbon (alkyl anion) donors, with the formation of five and seven membered rings.
WO 2010/037059 discloses pyridine containing amines for use in pharmaceutical applications.
U.S. Pat. No. 7,973,116 and US 2011/0224391 describe pyridyldiamide complexes in which the ligand is chelated in a tridentate fashion through three nitrogen donors (two amido and one pyridyl), with the formation of five and seven membered rings.
WO 2007/130307 describes hafnium complexes of heterocyclic ligands in which the ligand is chelated in a tridentate fashion through two nitrogen (one amido and one heterocyclic Lewis base) and one carbon (aryl anion) donor, with the formation of five and six membered rings.
Other references of interest include: 1) Domski, G. J.; Rose, J. M.; Coates, G. W.; Bolig, A. D.; Brookhart, M. “Living alkene polymerization: New methods for the precision synthesis of polyolefins” Prog. Polym. Sci. 2007, 32, 30-92; 2) Giambastiani, G.; Laconi, L.; Kuhlman, R. L.; Hustad, P. D. “Imino- and amido-pyridinate d-block metal complexes in polymerization/oligomerization catalysis” Chapter 5 in Olefin Upgrading Catalysis by Nitrogen-based Metal Complexes I, Catalysis by Metal Complexes, Springer, 2011; 3) Vaughan, A; Davis, D. S.; Hagadorn, J. R. in Comprehensive Polymer Science, Vol. 3, Chapter 20, “Industrial catalysts for alkene polymerization”, 2012; 4) Gibson, V. C.; Spitzmesser, S. K. Chem. Rev. 2003, 103, 283; 5) Britovsek, G. J. P.; Gibson, V. C.; Wass, D. F. Angew. Chem. Int. Ed. 1999, 38, 428; 6) Inorganic Chemistry (2010) 49, (11), 5143-5156; 7) JACS, (1997) 119(14), 3411-3412; 8) Organometallics, (1997) 16(26), 5857-5868; 9) Organometallics, (1998), 17(3), 466-474; and 10) Inorganica Chimica Acta, (1997), 263(1-2), 287-299.
There still is need for new catalysts complexes with enhanced performance in alkene polymerization.
Further, there is a need in the art for new catalysts with no symmetry (i.e., C1 point group symmetry) that can polymerize alpha olefins to yield crystalline polymers.